This invention relates to a rigid magnetic disk file, and more particularly relates to a clamp and method for clamping a stack of rigid disks with interleaved spacers to a hub and spindle to form a rigid disk file in which radial load is substantially eliminated.
All rigid disk drives comprise a disk clamp to provide a compressive load on the disk stack to hold the disks in place. These clamps have a wide variety of configurations. Generally, they are a disk or bell-shaped part that acts as a spring and is compressed by screws or bolts.
As rigid magnetic disks become smaller in diameter and track density increases, it is essential that the disks be maintained in parallel relationship to provide proper transducing between the read/write heads and disk recording surface. If the clamp imposes a radial load on the disk stack, it can cause distortion and droop of the disks. This, in turn, can cause misalignment of the heads and produce errors due to skew, missing bits, bit shift and/or signal distortion.
To avoid such distortion, the disk file should be assembled using a clamp that applies a purely compressive load. The clamp should also have a low spring constant to minimize variations in the load on the stack due to tolerance buildup and due to changes in stack dimensions with temperature.
U.S. Pat. Nos. 3,587,073; 4,065,799; and 4,672,488 disclose various disk clamp configurations. The IBM Technical Disclosure Bulletin in the March 1987 issue at p. 4346, and in the November 1977 issue at p. 2376, and in the March 1984 issue at p. 5444 disclose still other configurations. These constitute the most pertinent prior art known to applicants. None, however, discloses or suggests a clamp having the improved configuration disclosed and claimed herein.
There is a need for a rigid disk file clamp having a configuration that provides a low spring constant and that substantially eliminates radial distortion and load on the disk pack.